When given from the start of cardiopulmonary bypass, hANP protects the kidneys and heart, reduces the incidence of postoperative complications, and improves long-term outcomes, according to their paper in the April 27th Journal of the American College of Cardiology.

In the randomized NU-HIT trial for LVD, Dr. Akira Sezai from Nihon University School of Medicine, Tokyo, and colleagues administered either hANP or placebo to 133 patients with LV dysfunction undergoing CABG. The researchers point out that the starting dose of hANP was only 0.02 mcg/kg/min – much lower than the starting dose of 0.1 mcg/kg/min that’s given to patients with acute heart failure. Infusion at the initial dose continued until patients could take oral medication, at which point the dose was dropped to 0.01 mcg/kg/min and then discontinued 12 hours later.

The 68 patients in the treatment group received hANP in a continuous infusion for a mean of 2.8 days. The 65 patients in the control group received saline infusions for a mean 3.4 days.

There were no significant differences between the groups in 30-day and 180-day mortality, and overall survival rates did not differ significantly at 2, 5, and 8 years.

However, the rate of freedom from cardiac death was higher in treated patients vs controls (p = 0.028) at 2 years (98.5% vs 92.3%), 5 years (98.5% vs 85.5%), and 8 years (98.5% vs 85.5%).

Cardiac event-free rates were also significantly higher in the hANP group at those follow-up points.

Among the secondary endpoints, the treated group had a significantly greater mean LV ejection fraction and a significantly lower brain natriuretic peptide level than the control group as late as 1 year postoperatively.

“Even though hANP was only administered for a few days in the acute stage, a potent cardio- and renal-protective effect was demonstrated in long-term,” Dr. Sezai told Reuters Health by email.

Dr. Sezai believes hANP is compensating for the adverse effects of cardiopulmonary bypass. He pointed out that hANP is most effective in severely ill patients, such as those with chronic kidney disease, left ventricular dysfunction, acute myocardial dysfunction, thoracic aortic surgery, severe valve disease, or a ventricular assist device.